Parties left wondering if 2018 will be a repeat of 2016's surprise result; Kevin Corke reports from Cleveland ahead of President Trump's campaign rally.

For most of us, Election Day is Tuesday. But for more than 34 million Americans, Election Day has come and gone, because they have voted early. Early voting is more than 50 percent higher now than in the 2014 midterm elections – and that could be a good sign for Democrats.

Democrats are hoping the surge of new voters will aid their effort to capture majority control of the U.S. House and Senate from Republicans because, as The Hill newspaper reports, “turnout has increased the most among younger voters, minorities and people who rarely or never vote.” Most of these voters tend to support Democrats.

According to Michael McDonald of the Elect Project, 26 states and the District of Columbia have surpassed their 2014 early vote totals. Those states are Arizona, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Kansas, Louisiana, Maine, Maryland, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, New Jersey, New Mexico, Oklahoma, South Carolina, Tennessee, Virginia, Wisconsin and West Virginia.

Ten of those states have competitive Senate races and there are two high-profile and closely contested gubernatorial races in Florida and Georgia as well. And in two states with close Senate races – Nevada and Texas – more voters have voted early this year than voted early and on Election Day combined four years ago.

Across the country, the high levels of early voting indicate that when all the votes are counted voter participation is likely to reach the levels typically seen in presidential elections – much higher than participation in typical midterm elections. Historically, the more people who vote, the more likely it is that Democrats will win.

However, the historic levels of early voting have also been met in some place with voter suppression efforts by Republicans, along with voting machine tabulation problems that have never been seen or haven’t been seen since the 1950s and 1960s. I wrote about a number of these last week for Fox News. Those problems will also be a factor Tuesday and worth noting.

When you look at the record early voting you also see a gender gap that is also giving Democrats high hopes, because women voters are far more likely to support Democrats than men are. In fact, according to a Quinnipiac University poll women voters prefer Democrats over Republicans 58 percent to 42 percent. In sharp contrast, men prefer Republican candidates by a margin of 50 percent to 33 percent.

The gender gap, with higher numbers of women than men voting, could be good news for Democrats in a number of the same states that will determine the control of the Senate and House, as well as states with close gubernatorial elections.

These states include: Georgia, where there is a high-profile race for governor between Democrat Stacey Abrams and Republican Brian Kemp; Florida, with close Senate and gubernatorial races; and Indiana, Tennessee, Texas, Montana and Nevada – all with close Senate races.

There are several races that are worth watching for will early signs about what may happen on election night. These include:

The Indiana Senate race. Incumbent Democrat Joe Donnelly faces Republican former state Rep. Mike Braun. If Donnelly wins it would be a sign that other incumbent Democratic senators in red states may be able to win re-election as well.

Kentucky’s 6th Congressional District. Democrat and retired Marine Lt. Col. Amy McGrath is running against incumbent Republican Andy Barr. If McGrath beats Barr it could be a good sign for Democrats in other targeted seats to flip.

Virginia’s 7th Congressional District. This congressional seat has been held by Republicans for 50 years. Rep. Dave Brat, beat incumbent Eric Cantor – a member of the GOP leadership team – in a Republican primary four years ago, arguing that Brat wasn’t conservative enough. But now first-time candidate and former CIA Officer Abigail Spanberger has a shot at beating Brat. If Spanberger wins that is also a good sign that Democrats will win the House.

The Tennessee Senate Race. Republican Sen. Bob Corker is retiring and the open seat is a contest between former Democratic Gov. Phil Bredesen and Republican U.S. Rep. Marcia Blackburn. If Bredesen wins that could signal a good night for Democrats running in other Southern states and a bad night for Republican Senate candidates endorsed by President Trump. And yes, Taylor Swift’s endorsement of Bredesen may play a role in a race where early voting is up by about 1 million votes.

As we saw in 2016, election results can surprise pollsters and pundits. If Democrats fare poorly Tuesday it will be the second election in a row where more people voted but Democrats failed to meet expectations. That should raise a lot of questions about our elections and voting. There’s nothing more important than our democracy and that should concern every American.

Mary Anne Marsh is a Democratic political analyst and a principal at Dewey Square Group in Boston where she provides strategic counsel for Fortune 100 companies, non-profits and political campaigns.